This invention relates to compositions comprising an organic fluid, a surfactant and a thickening agent. The compositions are useful in many applications, particularly as a thickened oil flowable concentrate in which a pesticide may be incorporated.
There is a need to package pesticides in non-aqueous concentrates that can be diluted and dispersed to sprayable application concentrations in water. As conventionally understood, the term, pesticide, is inclusive of insecticides, herbicides, fungicides, and other active ingredients. When the pesticide active ingredient is soluble in, for example, a hydrocarbon fluid, an emulsifiable concentrate solution can be made by combining suitable surfactants with the hydrocarbon fluid and active ingredient. When the active ingredient is not soluble in an organic fluid and not chemically stable in water, an alternative approach is needed.
One approach is to suspend pesticide particles in an organic fluid/surfactant solution. For the particles to remain suspended and not settle to the bottoms of their containers, the solution viscosity, before pesticide particles are added, generally must be about 1000 cP. This could be achieved with viscous hydrocarbon oils; however, most viscous hydrocarbon oils are phytotoxic. Consequently, one would prefer to use lower viscosity organic fluids that are not phytotoxic and to then thicken or viscosify the fluids to a suitable viscosity with a thickening agent. Common thickening agents for organic fluids that could be used include soluble polymers and network or structure forming compounds such as fumed silicas, clays, and materials that are crystalline or semi-crystalline in the fluid at application temperature, but soluble in the fluid at an elevated temperature.
While all these agents can thicken organic fluids, many are not compatible with the surfactants needed to disperse the concentrate in water. For example, a small concentration (about 5 wt %) of a high molecular weight (about 2 million) polyisobutylene can thicken a mixed aliphatic hydrocarbon. When a blend of surfactants that is soluble in the aliphatic hydrocarbon and capable of dispersing it in water is added, the complete mixture does not form a solution, but instead separates into two phases. Such two-phase mixtures are not suitable for the present application. A similar amount of a hydrophobic fumed silica can also thicken a mixed aliphatic hydrocarbon; however, when the same dispersing surfactant blend is added, the viscosity of the solution drops back close to the level of the neat hydrocarbon fluid, and the mixture is not suitable for the present application.
Another approach is to use small molecule thickening agents that build intermolecular networks and viscosity via, for example, hydrogen bonding. One such system, described in U.S. Pat. No. 3,634,050, uses the reaction product of gamma-butyrolactone and cocoalkylamine to gel hydrocarbon fluids. This system can accommodate the addition of surfactants needed to disperse the fluid in water, but it has a sharp transition from a low viscosity liquid to a gelled semi-solid as the concentration in the hydrocarbon fluid is increased. Consequently, it, too, is an unsuitable thickening agent for the present application.
It is an objective of the present invention to provide a composition comprising an organic fluid, a surfactant and a thickening agent, which composition is flowable, uniform, has sufficient viscosity to stabilize a pesticide when incorporated therein, and is dispersible in water.
It is a further objective of the present invention to provide compositions comprising a pesticide and a thickened organic fluid/surfactant composition as described herein.
These and other objects and advantages of the present invention will be apparent to those skilled in the art from the following detailed description and claims.
In accordance with this invention, it has been found that the above and still further objects are achieved by providing a composition comprising at least one, or more, organic fluids, at least one, or more, surfactants, and as a thickening agent a compound having the formula 
where R is a linear or branched alkyl group having about 2 to about 6 carbon atoms, preferably 3 to 5 carbon atoms, or mixtures thereof; and
where X is a mixture of linear or branched alkyl or alkyl ether groups each having about 6 to about 21 carbon atoms, and from about 25 wt % to about 75 wt %, preferably 50 wt %, of the X groups have an average carbon number that is at least 4, preferably 6, more than the average carbon number of the other X groups.
The composition is uniform, flowable, and dispersible in water and has a viscosity that is from about 10 to about 1000 times larger than the viscosity of a corresponding composition having the same amounts of organic fluid and surfactant, but containing no thickening agent.
In accordance with this invention, it has been further found that there are provided useful pesticidal compositions comprising a pesticide and the thickened composition described herein, which thickened composition is uniform, flowable, dispersible in water, and has a viscosity that is from about 10 to about 1000 times larger than the viscosity of a corresponding composition having the same amounts of organic fluids and surfactants, but containing no thickening agent, and comprises at least one organic fluid, at least one surfactant, and as a thickening agent a compound having the formula 
where R is a linear or branched alkyl group having about 2 to about 6 carbon atoms, preferably 3 to 5 carbon atoms, or mixtures thereof; and
where X is a mixture of linear or branched alkyl or alkyl ether groups each having about 6 to about 21 carbon atoms, and from about 25 wt % to about 75 wt %, preferably 50 wt %, of the X groups have an average carbon number that is at least 4, preferably 6, more than the average carbon number of the other X groups.
The thickened organic fluid/surfactant compositions and the pesticidal compositions of the present invention are described in further detail as follows.
The thickened organic fluid/surfactant composition comprises:
(a) from about 82 to about 94 weight % of at least one, or more, organic fluid,
(b) from about 5 to about 15 weight % of at least one, or more, surfactant that is soluble in the organic fluid and is capable of dispersing the organic fluid in water, and
(c) from about 1 to about 3 weight %, as a thickening agent, of a compound having the formula 
where R is a linear or branched alkyl group having about 2 to about 6 carbon atoms, preferably 3 to 5 carbon atom, or mixtures thereof; and
where X is a mixture of linear or branched alkyl or alkyl ether groups each having about 6 to about 21 carbon atoms, and from about 25 wt % to about 75 wt %, preferably 50 wt %, of the X groups have an average carbon number that is at least 4, preferably at least 6, more than the average carbon number of the other X groups.
The composition is uniform, flowable, and dispersible in water and has a viscosity that is from about 10 to about 1000 times larger than the viscosity of a corresponding composition having the same amounts of organic fluid and surfactant, but containing no thickening agent.
Suitable organic fluids for use in the thickened compositions herein include, but are not limited to, aromatic and aliphatic hydrocarbons, alkyl esters, aromatic esters, glycol ethers, and mixtures thereof. Preferred fluids have flash points above 61xc2x0 C., and most preferred fluids have flash points above 93xc2x0 C. Neat fluid viscosities should also be below about 20 cP at 25xc2x0 C. Examples of preferred fluids include Exxsol(copyright) D110 Fluid, Exxate(copyright) 1000 Fluid, Isopar(copyright) M Fluid, Norpar(copyright) 13 Fluid, Norpar(copyright) 14 Fluid, and Aromatic Fluid, all available from ExxonMobil Chemical Company.
Suitable surfactants for use in the thickened compositions herein include, but are not limited to, alkanolamides, alkylarylsulfonates, alkoxylated alcohols, alkoxylated alkylphenols, alkoxylated amines, alkoxylated amides, alkoxylated fatty acids, glycerol esters, phosphate esters, quaternary surfactants, soaps, sorbitan derivatives, sulfates of alcohols, sulfates of alkoxylated alcohols, sulfonates of dodecyl and tridecylbenzenes, sulfosuccinates and derivatives, and other amphiphilic compounds that can be found in, for example, McCutcheon""s Volume 1: Emulsifiers and Detergents, 1997 North American Edition. Mixtures of the surfactants may be utilized.
The compound to be utilized as a thickening agent in the compositions herein may be prepared in any conventional manner. In a preferred embodiment, the compound is produced by reacting a lactone with an amine. More preferably, the thickening agent is produced by reacting at least one, or more, lactone, with at least two different primary alkyl or alkylether amines. In another preferred embodiment, the thickening agent may be the product of the reaction of at least two lactones with at least two different primary alkyl or alkylether amines. In a still further preferred embodiment, the thickening agent is produced by reacting together gamma-butyrolactone, epsilon-caprolactone, cocoalkylamine and hydrogenated tallowalkylamine.
Suitable amines for use herein include, but are not limited to, dodecylamine, hexadecylamine octadecylamine, oleylamine, cocoalkylamine, soyaalkylamine, tallowalkylamine, hydrogenated tallowalkylamine, isopropyloxypropylamine, isohexyloxypropylamine, 2-ethylhexyloxypropylamine, octyloxypropylamine, decyloxypropylamine, isodecyloxypropylamine, dodecyloxypropylamine, isododecyloxypropylamine, isotridecyloxypropylamine, tetradecyloxypropylamine, hexadecyloxypropylamine, octadecyloxypropylamine, and mixtures thereof.
Suitable lactones for use herein include, but are not limited to, beta-propiolactone, gamma-butyrolactone, gamma-valerolactone, epsilon-caprolactone, gamma-caprolactone, delta-valerolactone, and mixtures thereof.
An exemplary method for preparing the thickening agent used herein is as follows. The amine and lactone components are combined in a non-polar fluid at concentrations equal to or higher than the desired final concentrations thereof. The components are mixed well, with continuous agitation, to ensure complete reaction.
In a still further preferred embodiment of the present invention, the compound used as the thickening agent in the organic fluid composition herein has the formula 
where R is a mixture of C4 and C6 alkyl groups, and from about 25 wt % to about 75 wt %, preferably about 50 wt %, of the groups are C4 groups.
In a most preferred embodiment of the present invention, the thickened composition comprises:
(a) from about 82 to about 94 wt % of a substantially dearomatized (less than 1% aromatic compounds) mixed aliphatic hydrocarbon fluid having a boiling range of from about 200xc2x0 C. to about 300xc2x0 C.,
(b) from about 9 to about 11 wt %, preferably about 10 wt %, of a surfactant that is a mixture of ethoxylated amines and monoylphenol ethoxylates, and
(c) from about 2.1 to about 2.5, preferably about 2.3, wt % of a thickening agent that is the reaction product of gamma-butyrolactone, epsilon-caprolactone, cocoalkylamine and hydrogenated tallowalkylamine.
The pesticidal compositions of the present invention comprise a pesticide and a thickened composition as described herein, which thickened composition is uniform, flowable, dispersible in water and has a viscosity that is from about 10 to about 1000 times larger than the viscosity of a corresponding composition having the same amounts of organic fluid and surfactant, but containing no thickening agent, and comprises al least one, or more, organic fluid, at least one, or more, surfactant, and as a thickening agent, a compound having the formula 
where R is a linear or branched alkyl group having about 2 to about 6 carbon atoms, preferably 3 to 5 carbon atoms, or mixtures thereof and
where X is a mixture of linear or branched alkyl or alkyl ether groups each having about 6 to about 21 carbon atoms, and from 25 wt % to about 75 wt %, preferably 50 wt %, of the X groups have an average carbon number that is at least 4, preferably 6, more than the average carbon number of the other X groups.
The pesticidal composition may contain at least one, or more, pesticide suspended therein in an amount of from about 10 to about 80 wt %. Any pesticide may be utilized, and if desired, mixtures of pesticides may be utilized.
Examples of suitable pesticides include, but are not limited to, triazines like atrazine, simazine and propazine; sulfonylureas like nicosulfuron, tribenuron, and primisulfuron; carbamates like carbaryl and propoxur, imidazolinones like imazaquin and imazapyr; glyphosate and its carous salts; benzimidazoles like benomyl and thiabendazole; chlorothalonil; biologicals like various bacilli (Bacillus thuringiensis, Bacillus sphaericus) and spiosads; and strobilogens like azoxystrobin. This list is not meant to be exhaustive but to be representative of the types of pesticides that may be utilized herein.
Furthermore, it is desirable that the pesticide utilized has a melting point greater than 50xc2x0 C., and a hardness appropriate for grinding and/or dispersing to fine particles. It is further desirable that the pesticide utilized has a solubility in the organic fluid that is low, typically less than 1%, and preferably even lower. Exemplary of these pesticides are acephate, sulfonylurea herbicides, chlorothalonil, dithiocarbamate fungicides and glyphosate.
In preparing the pesticidal compositions herein, there may be suitably utilized any of the organic fluids, surfactants and thickening agents described as being suitable in preparing the thickened compositions of the present invention.
With respect to the organic fluid used in preparing the pesticidal compositions of the present invention, it is preferred that the organic fluid not be reactive either in and of itself, or toward the pesticide. The low solvency aliphatic hydrocarbon fluids are most preferred. Exemplary are the dearomatized mixed aliphatics like Exxsol(copyright) D Fluids, isoparaffins like Isopar(copyright) Fluids and normal paraffins like Norpar(copyright) Fluids, all available from ExxonMobil Chemical Company.
If desired, other conventional additives may be incorporated into the thickened organic fluid/surfactant compositions and/or the pesticidal compositions of the present invention. In particular, other surfactants may be included to enhance the stability of the suspension of pesticide particles within the thickened organic fluid/surfactant composition.
The compositions of the present invention may be prepared by any method known in the art. In preparing the compositions of the examples herein, the components of the composition were added to a jar, raised to a temperature sufficient to melt all components, mixed well for about 15 minutes, and allowed to stand.